Electroluminescent device



Dec. 8, 1959 B. ROSENBERG I 2,916,630

ELECTROLUMINESCENT DEVICE Filed Nov. 28, 1958 2 Sheets-Sheet 1 INCIDENTENERGY FIG.

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United States Patent ELECTROLUMINESCENT DEVICE Barnett Rosenberg, NewYorlr, N.Y., assign'or to Westinghouse Electric Corporation, EastPittsburgh, Pa., a corporation of Pennsylvania Application November 28,1958, Serial'No. 776,817

' 13 Claims. (Cl. 250-213 This invention relates to electroluminescentdevices and, more particularly, to energyand image-amplifying deviceshaving fast response and a high degree of sensitivity.

Energyphotoconductor material and electroluminescent phosphorcombinations are well known and are generally described in US. PatentNo. 2,650,310, dated August 25, 1953. Such devices as described in theabove-mentioned patent comprise a layer or stratum of photoconductormaterial and a separate layer or stratum of electroluminescent phosphormaterial, which separate layers are sandwiched together between twoelectrodes. When an A.C. potential is applied across the electrodes andthe photoconductor material, or a portion thereof, is irradiated withsome sort of external energy, such as X-rays or light for example, theelectrical impedance of the photoconductor stratum decreases at thatportion which is irradiated. This in turn places the alternatingelectric field across the electroluminescent phosphor layer per serather than the combined phosphor-photoconductor layer, thereby causingthe phosphor to emit light because of the i creased field. With such adevice, the photoconductor layer can be represented as aparallel-connected resistance and capacitance. The electroluminescentlayer can also be represented as a parallel-connected resistance andcapacitance. Both of these parallel-connected R.C. circuits areconnected in series across the source of energizing A.C. potential. Whenthe photoconductor is not irradiated or otherwise energized, theresistances of both the photoconductor and the electroluminescent layer.are quite high. In order that most of the energizing potential isapplied across the photoconductor under so-called dark conditions, thecapacitance of the photoconductor must be small as compared to thecapacitance of the electroluminescent portion of the device. This inturn requires that thickness of the photoconductor be made great ascompared to the thickness of the electroluminescent phosphor layer. Athick photoconductor layer, however, impairs resolution and sensitivityand in addition, the most sensitive photoconductor materials are quiteslow in response.

It is the general object of this invention to avoid and overcome theforegoing and other difliculties of and objections to prior-artpractices by the provision of an photoconductor layers which are fast inresponse and are very sensitive to excitation. It is an additionalobject to provide'various embodiments and constructional details for andimage-amplifying devices.

The aforesaid objects of the invention, and other and image-amplifyingdevices comprising energy-amplifying "Fee.-

' objects which will become apparent as the descriptio the electrodesbounding the separate strata can be made common if desired or fourseparate electrodes can be used with a direct electrical connectionbetween two of them.. The outermost electrodes bounding the separatestrata," which electrodes are not directly electrically. connected I toone another, are adapted to be connected across a source of D.C.potential. The remaining electrodeorj' electrodes are adapted to becommutated' in an alternating and rapid fashion in order alternately andrapidly to place such electrode or electrodes at a potential level whichat least approaches'the potential level of the outermost uncommutatedelectrode which is adjacent to the electroluminescent phosphor. Thisallows the device to operate from D.C'. potential excitation with astoragetype' operation and capacitive elfectsfof the photoconductorstratumand electrodes associated with same are minimized. The result isthat the device can be made extremely sensitive with respecttoamplifying energy and energy-images and fast-response photoconductormaterials can be used in very thin layers if desired.

For a better understanding of the invention reference should be hadtothe accompanying drawings wherein;

Fig. 1 is a sectional elevation of an energy-amplifying device with thecommutator means therefor shown in per: spective view;

Fig. 2 is a diagrammatic representationof the embodi ment as shown inFig. 1; p v

Fig. 3 is analternative'embodimentfof the device as shown in Fig. 1Wherein 'the' phosphor and photoconductor strata are formed with anappreciable spacing therebetween;

Fig. 4 isa diagrammatic representation of a multielement device whichcan operatev as an image amplifier;

Fig. 5 is a fragmentary, enlarged perspective view," partly in section,of one embodiment ofan image-a rfv plifying device; 7

Fig.- 6 is' a fragmentary sectionalyenlargement, ofja portion of thedevice as shown, in Fig. 5, further illustratingconstrnctional detailstherefor; I Fig. 7 "s a fragmentary, enlargedperspective view, shownpartly in section, illustrating an .alternative embodiment of the deviceas, shown in Figs. Sand 6;,

Fig. 8 is an alternative embodiment of an image-a'm-l plifying devicewherein the photoconductor'andelectroluminescent phosphor strata. areconsiderably spacedfrom one another, with a commutating mechanisminterposed therebetween;

Fig. 6 is a fragmentary front elevation of the contact plate used tocommutate the individual amplifying elementscomprising the device asshown in-Fig. 8.

With specific reference to the form of the invention shown in thedrawings, the numeral 10 in Fig. 1 illustrates anenergy-amplifyingdevice which can also be" used as one element of an image-amplifyingdevice. The device 10 generally comprises a first electrode 12 which istransmissive to the energy-amplified radiation to be presented by thedevice, a second electrode 14 and the "electrode 14 which also acts 'toenergize the stratum 16 comprising electroluminescent phosphor. Anadditiqual electrode 12!) is placed on the other side of the stratum 1read this slashed; 2. is t ans s to the energy which is to be receivedby the device 10. The area of each of the electrodes can varyconsiderably. In h s 9 2 SiRlPrPQi ener -a p tude deviee. sh slashed? anha ne o om o e sg are inch t bnesqasrs t f r example 5 th sas of a imae.- am plify'ii g device, the effective area of the electrodes willusually be made considerably smaller. A 13.0. liQ sflt t l ur e 2 isconnected o the ele t ode 1. nd by means of lead conductors 24 and 26respectively. A W i e m t o 8 el ctr c l y con e between the electrodes12 and 14 in order alternately an ra d t Pl e electr de 4 a a Poten ia ee w it r least ap ss s th p stlt l e el or he qls t sd 2- T ommuta 2!?ssrn riss a me estab e. dru 0. ca ryin the e n 2 3 i ul tin see titan3'2- s he b ush 41s n ire ee ta t ith t e nduc in t i drum .9 an 1. p tn which a utn at tl 9 the e se rede 15 s r pidly di a slh D-C- squ j.22. ca deliver a pot ntial of '100 yolts for example.

. The d v e 1 s s o n F 1 can b sou ri st d to amplify any energy whichcan be propagated through vacuum such as X-rays, ultraviolet radiations,visible, light, infrared radiations or cathode rays. This energy is"converted intoenergy-amplified radiations, which will normally take theform of visible light. A diagrammatic representation of the deviceillustrated in Fig, 'l is shown in Fig. 2 The photoconductor stratum 18is represented as s i ns ich is uit h wh n he ho o onductor stratum isnot energized and which varies inversely with the intensity of theenergy to be received by the device 10.' In other words, the strongerthe exciting energy signal, he lower the resistance or" thephotoconductor stratum 18 A lowered resistance of the photo- Conductorstratum 18 allows one side of the capacitor formed bytheelectroluminescent stratum 16 and the bounding electrodes 12 and 14 tocharge, with the rate of charging being determined by the intensity ofthe re; ceived energy. After a predetermined period, which can be secondfor example, the commutator 2,8 has rotated sufficiently to place theelectrode 14 at substantially the same potential level as the electrode12. This sudden dissipation of charge causes the electroluminescent cellwhich is formed by the electrodes 12 and 14- and theiph'osphor stratum16 to emit a sudden flash of light, the intensity of which varies withthe amount of charge dissipated. The device thus operates on thePriuciple that a D.C charge is accumulated and then is"suddenly,discharged and the resulting change in electric field across theelectroluminescent phosphor. causes sameto"er'nit'light.' Since thecapacitive eitects of the Dh P' QttClQJCtQIT'. and its boundingelectrodes are minimizedfbythis arrangement, the photoconductor. stratum18 can be made as thin as desired and in addition, extremely fastphotoconductor materials can be used, since even relatively insensitivephotoconductor materials when used in thin layers, have a high efiectivesensitivity with respect to exciting energy.

As a specific example, the electrode 12 can'be formed of lighttransmitting"tin oxide deposited onto a, glass supporting plate 36. Theelectroluminescent stratum 16 can comprisean electroluminescent phosphorsuch as zinc sulfide activated by copper and coactivated by chlorine andsuch phosphors are well known. Desirably the phosphor is embeddedthroughout a dielectric material ,"such as by embedding thefinely-divided phosphor in equal; amount by weight of dielectric.material. withfsuch a construction thedielectric material should belight transmitting and polyvinyl-chloride acetate or h xs t al P a ti r.ssrami d sls r ma r al v well known. If desired anadditional qf'di. tip. anbe. nc d sf s i. hefe e ga d ft'q s a a e. vers. of mount indielectric material can be included between the electrodes 12 and 14.Such constructions are conventional in the electroluminescent art. Theelectrode 14 can be formed of vacuum-metallized aluminum or it can beformed of copper iodide for example. If the energy which is to beamplified comprises visible light or energy which is capable of excitingthe electroluminescent phosphor to visible luminescence, the electrode14 can be formed of a material which is not transmissive to visiblelight or to the energy which is to be amplified. As an example, iiultraviolet .or visible radiations are to be amplified, the electrode 14can be formed of vacuum-metallized aluminum deposited as an opaque layerand if cathode rays are to be amplified, an additional layer of glasscan also be included adjacent the electrode 14. The thickness oi thephosphor dielectric layer 16 is in no way critical and as an example isone mil. The electroluminescent phosphor can also be included between hislss wtlss .12 and 15 th no admix or separate dielectric or the phosphorcan be utilized in the form of a thin him, such thin films of phosphorbeing generally described in Feldman and OHara article appearing inJournal of the Optical Society of America, vol. 47, No. 4, pages 300-305(April 1957).

The photoconductor stratum 18 can beformed of variu m teri ls dep din pe ne y hi h i to e amplified. As an example, the photoconductor stratum18 can be formed of powdered cadmium sulfide, which if desired can haveadmixed therewith a small amount of dielectric material such as 5% byweight. The admixed dielectric, if used, can be similar to thedielectric used with the phosphor, but the amount should be limited sothat the stratum 18 can when excited conduct D.C. Powdered cadmiumsulfide varies in resistance under irradiation by longer Wavelengthvisible radiations or X-rays. Cadmium selenide and cadmium telluride canbe substituted for'the cadmium sulfide and are also similar in response.Powdered zinc-cadmium sulfide is not as sensitive a photoconductor ascadmium sulfide per so, but can be made broadly responsive to ditferentwavelengths by varying the zinc to cadmium ratio, as is Well known, andsuch a photoconductor can respond to a broad range extending from 3650AU. to 7000 A.U., as well as to X-rays. Lead sulfide is sensitive toinfra red radiations. The foregoing inorganic photoconductor substancescan also be evaporated as thin continuous films by means of thetechnique as specified hereinbefore for. preparing thin films of zincsulfide electroluminescent phosphor. These thin films of inorganicphotoconductor substances are quite sensitive and are somewhat faster indecay time than the powdered inorganic photoconductor materials. It isalso possible to use organic photoconductor substances. Organicphotoconductor substances are normally quite fast in response and decay,but are somewhat less sensitive than the powdered inorganicphotoconductor. substances, although in the. present device this. is'not particularly"detrimental since the photoconductor stratum 18 can bemade extremely thin in order to enhance the etiective sensitivity of thephotoconductor material. As an example, anthracene photoconductormaterial is responsive to ultraviolet radiations to decrease inresistance and under relativelylow intensity irradiation has a decaytime in the order of 0.01 second; Naphthacene is responsivetoultraviolet and to visible radiations up to the yellow portion of thespectrum, which radiations cause this photoconductor to decrease inresistance. Pentacene is responsive to all visible radiations to vary inresistance and is relatively fast in decay time. In th case organicphotoconductor substances are utilized, it is necessary that thepositive pole of the applied D,C. po-

tential is connected to the electrode which isadjacent the surface oithe photoconductor material which is adaptcase of inorganicphotoconductoh substances, it does not usually matter which pole of theapplied DC potential is connected to the electrode layer adjacent to thephotostance need not have a great thickness as compared to theelectroluminescent phosphor stratum, as in prior art energyandimage-amplifying devices. This is because the photoconductor substanceacts primarily as a valve in order to accummulate a DC. potential on anelectrode which is adjacent to the stratum comprising electroluminescent phosphor.

a thickness of ten microns. This thickness can be varied considerably.The electrode '20 can be formed of copper iodide or of tin oxide formedon an additional glass support (not shown). Q

In Fig. 3 is shown a device embodiment 38 which generally corresponds tothe device embodiment 10 as shown in Fig. 1 except that the electodemembers which bound the separate strata comprising photoconductormaterial 18 and electroluminescent phosphor 16 are physically separatedfrom one another with one of the electrodes 40 bounding thephotoconductor material maintained in electrical continuity with one ofthe electrodes 42 bounding the electroluminescent phosphor. Anadditional supporting plate glass 44 is provided adjacent the electrode40, which can be formed of tin oxide for example. The electrode 42 whichis electrically connected to the electrode 40 can be formed ofvacuum-metallized aluminum for example. Other than these indicateddifferences, the device 38 can be identical to the device 10 as shown inFig. 1. With a device of this general description, brightnessamplifications of 242 and energy amplifications of 150,000 have beenachieved.

The device embodiments 10 and 38 as shown in Figs. 1 and 3 representeither an energy-amplifying device or one element of an image-amplifyingdevice wherein a plurality of such elements are arranged inadjacentrelationship in order to present a composite image. Animage-amplifying device 46 is represented diagrammatically in Fig. 4,wherein three individual energy-amplifying elements are positioned inadjacent relationship to act as an image amplifier. Each of theindividual elements as shown in Fig. 4 can be constructed in accordancewith either of the embodiments 10 or 38 as shown in Figs. 1 and 3. Inthe device embodiment 46, the electrodes which are used with each of theelements comprising the image amplifier are electrically insulated fromone another and each has an area corresponding to the degree ofresolution which is desired for the image-amplifying device, such asfour square mils for example. In some cases, the outermost boundingelectrodes can be made continuous in nature, as will be describedhereinafter, and in such construction only a small portion of each ofthe outermost continuous electrodes will cooperate with the very smallelectrode member oppositely disposed thereto, which small electrodemember has an area preselected in accordance with the degree of reso--lution desired for the device.

In Fig. is shown in perspective view a portion of an image-amplifyingdevice 48 which comprises a plurality.

of individual energy-amplifying elements 50. The device 48 comprises afoundation layer 52 which can be-formed of an opaque,electrically-insulating material such asglass-bonded mica or ureaformaldehyde for example, having a plurality of aligned apertures 54laterally drilled Thus the photoconductor canbe madeas thin as desiredand as an example, can have therethrough. The thickness of thefouiidation' layer 52'.

can vary considerably and as an example is 1-2 mils. Photoconductormaterial 56 is retained in alternate lines of the apertures andelectroluminescent phosphor 58 is retained in the remainder to saidapertures. Each aperture containing photoconductor material 56 and anadjacent aperture containing electroluminescentv phosphor 58 forms oneelement 50 of the image-amplifying device 48 and the area of each ofthese elements 50 is preselected in accordance with the degree ofresolution desired for the image-amplifying device 48. Each line ofphotoconductor-filled apertures is electrically connected at one side6001': the foundation layer 52 by means of first conducting strips ;62of tin oxide for example. Each alternate line of apertures containingeIectrolumineScentphOsphor 58 is also electrically connected by secondconductingstrips -64 of tin oxide for example. Each of these conductingstrips 62 and 64 can be formed on a. glass plate 66 and are adapted tohave a DC. potential;

applied thereacross. The other side 68 of the foundation 52.has includedthereon a plurality of small conducting segments 70which serve toconnect electrically one side of the photoconductor material 56 with oneside of the electroluminescent phosphor 58 of each element 50. Thesesmall conducting segments 70 can be formed by vacuum-metallizingaluminum over selected portions of side 68 of the foundation layer 52.Each element 50 comprising the image-amplifying device 48 can begenerally similar to the device embodiment 38 shown in Fig. 3. Forpurposes of commutation, a contact plate 72, which is adapted toreciprocate in a rapid fashion, alternately contacts the conductingsegments 70. contact plate 72 can be formed of metal-backed plastic suchas polyethylene terephthalate having a layer 73 of conducting materialsuch as copper affixed to the side thereof which is adapted to contactthe segments 70. This conducting layer 7 3 is electrically connected'tothe second tin oxide electrode strips 64. When the contact plate 72 isvibrated in a rapid manner to contact the conductingv segments 70, thishas the effect of placing.

the conducting segments 70 at the same potential as the second tin oxideconducting strips 64. If the photo conductor material 56 of an element50 has not been excited with light or other energy to be amplified, noD.C. charge will have accumulated on the conducting member 70 associatedwith the element. conductor portion 56 of an element 50 has beenirradiated with energy to which it is sensitive, a DC. charge will haveaccumulated on the appropriate conducting member 70 in proportion to theamount of light or other energy which excited the photoconductormaterial. The resulting rapid discharge of all of the accumulatedcharges will cause the electroluminescent portions of the device to emitflashes of light. With a sufiiciently rapid cycling period, such as 60cycles per second, the eye will blend the resultant flashes together towhat appears to be continuous light.

In Fig. 6 is shown an enlarged fragmentary view of one of theenergy-amplifying elements '50 of the device 48 as shown inFig. 5. Asshown more. clearly in this view, when the radiation which is to beamplified, such as visible light, irradiates the photoconductorsubstance,

such flash varying in intensity with the magnitude of the accumulatedcharge which is dissipated, Thevibrator for the contact plate 72 cancomprise any conventional electrical vibrator which actuates the plate72 through a conventional connecting shaft 74 aflixed to the metalbacking of the contact plate 72.

In the embodiment as shown in Figs. 5 and 6, the

The

If the photoradiationsenergy-image. is viewed from the same face of thedevice. For some purposes, it is desirable to present thev amplifiedradiationrenergy-image on the face of the device whichis opposite. totheface of. the device which is adapted to receive the energy which isto be amplified! Such an embodiment. 76 is shown in. Fig. 7.Thisembodiment generally. corresponds to the. device. embodiment 48asshowninFig. 6except that the reciprocable contact plate. 78 is. providedwith a plurality of apertures 80 which are. alignedwith theelectroluminescent portions 82' of each of. the energyamplifyingelements 84 which comprise. the device 76. modified. in. that.a raised contactingmember 86 isprovided tocontact electricallythe.contact plate 78" at the lower extreme of. its throw. Eachraisedcontacting mem ber 86 is..electrically connected to a transparentconducting segment 88, one eachofwhich. coversaone. side of each of the.amplifying elements 84.comp.rising .the device 76. In addition,the:conducting strips 90, whichare adjacent the electroluminescentportion'82 of each element 84 and through which D.C. energizingpotentialis applied, not be made radiation or energy-transmitting and can befabricated of copper strips for example. Other than these indicateddifferences, the device 76 .as shown in Pig. 7 corresponds to the device48 as shown. in Figs. and 6.

As a further alternative device embodiment,-.the photoconductor andelectroluminescent portions ofeach element comprising an imaging devicecan be physically separated fromone another by any desired. distance andsuch a device embodiment 92 is shown in Fig, 8'. This device embodimentcomprises a first electrode 9.4 which is transmissive to theenergy-amplified radiationswhich are to be presented and this. electrodecan be. fabricated of tin oxide on a glasssupporting plate 96.. Over thefirst electrode 94 is placed a stratum 98 comprising electroluminescentphosphor, such as described hereinbefore. Over the stratum comprisingelectroluminescentphosphor is placed a composite electrode 100.comprising-a plurality of small electrode segments, each of-which has anarea corresponding to the degree of resolutiondesired for they imagingdevice. The photoconductor: portions of theimaging device 92 are similarin construction to the. electroluminescent phosphor portion. of thedevice in that the photoconductor material stratum102 isbounded. by acontinuous electrode 104 and composite electrode 106. The stratum 102can be similar to those described. hereinbefore. As in the case of thecomposite electrode. 100, the composite electrode 106 is formed as aplurality of small conducting segments eachhaving an area correspondingto the degree of resolutiondesired for the device. The electrode 104 canbe formed of tin oxide on a glass supporting layer 108. Each of thesmall segmentscomprising the composite electrodes100 and 106 can beformed of small copper segments for example, with each small segmentelectrically insulated from. the segment adjacent thereto. The.outermost bounding electrodes 94 and 104 are adapted to. be connectedacross. a source of DC. potential. Each individual segment comprisingthe composite electrode. 100 is maintained in electrical continuity withan individual segment comprising the composite electrode. 106. Inaddition a commutating means 109, which can comprise a vibrating contactplate 110, is providedintermediate the electroluminescent andphotoconductor portions. of the device .92, in-order alternately andrapidly to place each segment comprisingthe composite electrode 100 at apotential level which. at least approaches the potentialleveloftheelectrode v94 Thecontact plate110-is shown inFig. 9andcomprises aconductingplate member-such as copper having a pluralityof apertures 112 provided therethrough. Each of the apertures 112'contains an insulating bushing..114' and a center conducting member Thisembodiment. is. further 116v within the bushing 11T4. Spring loadedelectrical contacts 118are laterally reciprocable within electricallyinsulating retaining members 120positioned on either side of contactplate 110. In the operation of the commutating means 109, whenthe plate110 is not actuated, one of each of the segments comprising thecomposite electrode106.will'bemaintained in electrical continuitywith-one ofeach of the segments comprising the composite electrodethrough the center conducting members 116"in" contactplate 110. When thecontact plate 'is vibrated from the position as illustrated in Fig. 8,the spring-loaded electrical contacts 118' will be placed in directelectrical contact with the body of the contact plate 110,- which inturn is electrically connected to theelectrode 94. This will place eachof the small segments comprising the composite electrodes 100 and 106 ata potential level which is substantially the-same as the potential levelof "the first electrode 94. Vibration of the contact plate can beaccomplished'by any conventional electrical vibrating. or equivalentdevice. Theelectromechanical commutation means 109 can be replaced by anelectronic commutating means if ergy-amplified radiations are viewedfrom the glasssup porting plate 96.

In any of. the image-amplifying device embodiments as illustrated anddescribed hereinbefore, excellent resolution can .be obtained. by virtueof thevery thin photoconductor. layers which can be'utilized: In"addition, extremely fast photoconductor substances ican'be utilizedwhile stillobtaining ahigh degree of effective sensitivity, since evenrelatively-insensitive photoconductor materials display, ahigh effectivesensitivity when used1in= very-thin layers.

Any of the foregoing devices'as illustrated and described hereinbeforecan be used to amplify. extremely weak energy or energy-images and topresent suchlenergy or energy-images as amplified radiations. For such ause, the devices can be operated so-as to accumulate energy over arelatively long period of time andito dis sipate such accumulated energyin a rapid fashionto cause the electroluminescent portions of the.devicesto produce light varyingin intensity inproportion to themagnitudeof the accumulated charges. For suchoperation, the commutatingmechanisms asdisclosed hereinbefore can be slowed down or dispensed:with if desired. In the case the commutating mechanismsare. dispensedwith, amanual switching. arrangement can be used to dissipate inarapid'fashionany accumulated" charges on the innermostelectrode boundingthe electroluminescent stratum. The foregoingdevices can thus be made tooperate on a one-shot principle andthe resulting'energy-amplifiedradiations can be photographed if desired. In addition, in any of theforegoing device embodiments, the electrodes or electrode segmentsassociatedwiththe photoconductor material need not have the samedimensions as the electrodesor electrode segments associated with the.electroluminescent phosphor. The presented radiation energy orenergy-image can thus beexpanded or decreased considerably with respectto the-area-of the energy or energy-image to be amplified As -an.example, the electrodes or electrode segments associated with thephotoconductor material can have an area which is one-tenth the area ofthe electrodes'or'electrode segments associated Wl'th'thBelectroluminescent phosphor.

It will'be recognized that the objects of the invention have beenachieved by providing energy-amplifying andimage-amplifying deviceswhich are extremely sensitive and which can be made to operate with goodresolution. In addition, there have been provided energyandimage-amplifying devices which can utilize comparatively thinphotoconductor materials which are very fast in response and are verysensitive to excitation. There have also been provided variousembodiments and constructional details for energy-amplifying andimageamplifying devices.

While various embodiments have been illustrated and describedhereinbefore, it is to be particularly understood that the invention isnot limited thereto or thereby.

I claim:

1. A device for receiving energy which can be prop: agated throughvacuum and presenting such received energy as energy-amplifiedradiation, said device comprising, a first electrode transmissive toenergy-amplified radiation to bepresented by said device, a secondelectrode, a stratum comprising electroluminescent phosphor sandwichedbetween said electrodes, a, stratum comprising photoconductor material,the electrical resistance of said stratum comprising photoconductormaterial varying inversely with the intensity of energy to be receivedby said device, a pair of electrode members provided on either side ofsaid stratum comprising photoconductor material, one electrode of saidpair of electrode members transmissive to energy tobe received by saiddevice, the other electrode of said pair of electrode members maintainedin electrical continuity with said second electrode, said firstelectrode and said one of said pair of electrode members adapted to beconnected across a source of D.C. potential, and means for rapidlyplacing said second electrode at a potential level at least approachingthe potential level of said first electrode.

2. A device for receiving energy which can be propagted through vacuumand presenting such received energy as energy-amplified radiation, saiddevice comprising, a first electrode transmissive to energy-amplifiedradiation to be presented by said device, a second electrode, a stratumcomprising electroluminescent phosphor sandwiched between saidelectrodes, a stratum comprising photoconductor material, the electricalresistance of said stratum comprising photoconductor material varyinginversely with the intensity of energy to be received by said device, apair of electrode members provided on either side of said stratumcomprising photoconductor material, one electrode of said pair ofelectrode members transmissive to energy to be received by said device,said second electrode forming the other electrode of said pair apotential level at least approaching the potential level 't of saidfirst electrode.

3. A device for receiving energy which can be propagated through vacuumand presenting such received energy as energy-amplified radiation, saiddevice comprising, a first electrode transmissive to energy-amplifiedradiation to be presented by said device, a second electrode, a stratumcomprising electroluminescent phosphor sandwiched between saidelectrodes, a stratum comprising photoconductor material, the electricalresistance of said stratum comprising photoconductor material varyinginversely with the intensity of energy to be received by said device, apair of additional electrode members physically separated from saidfirst and second electrodes and provided on either side of said stratumcomprising photoconductor material, one electrode of said pair ofadditional electrode members transmissive to energy to be received bysaid device, the other electrode of said pair of additionalelectrodemembers maintained in electrical continuity with said secondelectrode, said first electrode potential, and means for alternately andrapidly placing said second electrode at apotential level .at leastapproaching the potential level of said first electrode.

4. An elemental portion of a device for receiving an elemental portionof an image comprised of energy which can be propagated through vacuumand presenting such received energy-image elemental portion asenergy-amplified radiation, said device elemental portion comprising, afirst electrode transmissive to the energy-amplified radiation to bepresented, a second electrode, a stratum comprising electroluminescentphosphor sandwiched between said first and second electrodes, a stratumcomprising photoconductor material, the electrical resistance of saidstratum comprising photoconductor material varying inversely with theintensity of the energy to be received by said device elemental portion,a pair of electrode members provided on opposite sides of said stratumcomprising photoconductor material, one electrode of said pair ofelectrode members adapted to receive incident thereon and transmissiveto the energy to be received by said device elemental portion, the otherelectrode of said pair of electrode members maintained in electricalcontinuity with said second electrode, said one electrode of said pairof electrode members and said first electrode adapted to be connectedacross a source of D.C. potential, and means for. rapidly placing saidsecond electrode at a potential level at least approaching the potentiallevel of said first'electrode.

5. An elemental portion of a device for receiving an elemental portionof an image comprised of energy which can be propagated through vacuumand presenting such received energy-image elemental portion asenergy-amplified radiation, said device elemental portion comprising, afirst electrodetransmissive to the energy-amplified radiation to bepresented, a second electrode, a stratum comprising electroluminescentphosphor sandwiched between said first and second electrodes, a stratumcomprising photoconductor material, the electrical resistance of saidstratum comprising photoconductor material varying inversely with theintensity of the energy to be received by said device elementalportion,a pair of electrode members provided on opposite sides of said stratumcomprising photoconductor material, one electrode of said pair ofelectrode members adapted to receive incident thereon and transmissiveto the energy to be received by said device elemental portion, saidsecond electrode forming the other electrode of said pair of electrodemembers, said one electrode of said pair of electrode members andsaid'first electrode adapted to be connected across a source of D.C.potential, and means for alternately and rapidly placing said secondelectrode at a potential level at least approaching the potential levelof said first electrode.

6. An elemental portion of a device for receiving an elemental portionof an image comprised of energy which can be'propagated'through vacuumand presenting such received energy-image elemental portion asenergy-amplified radiation, said device elemental portion comprisandsaid one of said pair of additional electrode mem- 'bers adapted to beconnected across a source of D.C.

ing, a first electrode transmissive to energy-amplified radiation to bepresented, a second electrode, a stratum comprising electroluminescentphosphor sandwiched between said first and second electrodes, a stratumcomprising photoconductor material, the electrical resistance of saidstratum comprising photoconductor material varying inversely with theintensity of the energy to be received by said device elemental portion,a pair of additional electrode members physically separated from saidfirst and second electrodes and provided on opposite sides of saidstratum comprising-photoconductor material,one electrode of said pair ofadditional electrode members adapted to receive incident thereon andtransmissive to the energy to be received by said device elementalportion, the other electrode of said pair of additional electrodemembers maintained in electrical continuity with said second elec- 11trode, said one electrode of said pair of additional electrode membersand said first electrode adapted to be connected across a source of DC.potential, and means l'or alternatelyand' rapidly placing said secondelectrode at a potential level at least approaching the potential levelof said first electrode.

7. An elemental portion of a device for receiving an elemental portionof an image comprised of energy which can be propagated through vacuumandpresenting such received energy-image elemental portion asenergy-amplified radiation, said device elemental portion comprising, afirst electrode transmissive to energy-amplified radiation to bepresented, a second electrode, a stratum comprising electroluminescentphosphor sandwiched between said first and second electrodes, astratumcomprisingphotoconductor material, the electrical resistance of saidstratum comprising photoconductor material varying inversely with theintensity of the energy to be received by said device elemental portion,a pair of electrode members provided on opposite sides of said stratumcomprising material, one electrode of said pair of electrode membersadapted to receive incident thereon and transmissive to the energy to bereceived 'by said device elemental portion, the other electrode of saidpair of electrode members maintained in electrical continuity with saidsecond electrode, said one electrode of said pair of electrode membersand said first electrode adapted to be connected across a source of DC.potential, and electrically-actuated make-and-brea'k means foralternately and rapidly placing said second electrode at a potentiallevel at least approaching the potential level of said first electrode.

8. An image-amplifying device for receiving images comprised of energywhich can be propagated through vacuum and. presenting amplifiedradiation images which correspond to such received energy-images, whichdevice comprises, a first electrode transmissive to amplified radiationimages to be presented, a second electrode formedof a plurality ofindividual small conducting segments electrically insulated from oneanother and each having an area corresponding to the degree ofresolution desired for said device, material comprisingelectroluminescent phosphor sandwiched between said first and secondelec* trodes, a stratum comprising photoconductor material, theelectrical resistance of said stratum comprising photoconductor materialvaryinginversely with the intensity of the energy comprisingenergy-images to be received by said device, a pair of electrode membersprovided on or posite sides of said stratum comprising photoconductormaterial, one of said pair of electrode members transmissive toenergy-images to be received by said device, the other of said pair ofelectrode members comprising a plurality of individual small conductingsegments electrically insulated from one another and each having an areacorresponding to the degree of resolution desired for said device, eachindividual small conducting segment comprising said other of said pairof electrode members electrically connecting to an individual segmentcomprising said second electrode, said first electrode and said one ofsaid pair of electrode members adapted to be connected across a sourceof DC. potential, and means for alternately and rapidly placing saidsecond electrode at a potential level at least approaching the potentiallevel of said first electrode.

9. An image-amplifying device for receiving images comprised of energywhich can be propagated through vacuum and presenting amplifiedradiation images which correspond to such received energy-images, whichdevice comprises, a first electrode transmissive to amplified radiationimages to be presented, a second electrode formed of a plurality ofindividual small conducting segments electrically insulated from oneanother and each having an area corresponding to the degree ofresolution desired for said device, material comprisingelectroluminescent phosphor sandwiched between said first and secondelectrodes, a stratum comprising photoconductor material, the electricalresistance of said startum comprising photoconductor material varyinginversely with the intensity of the energy comprising energy-images tobe received by said device, a pair of electrode members provided-onopposite sides of said stratum comprising photoconductor material, oneof said pair of electrode members transmissive to energy-images to bereceived by said device, said second electrode forming the otherelectrode of said pair of electrode members, said first electrode andsaid one of said pair of electrode members adapted to be connectedacross a source of DC. potential, and means for alternately and rapidlyplacing said second electrode at a potential level at least approachingthe potential level of said first electrode.

10. An image-amplifying device for receiving images comprised of energywhichcan be propagated through vacuum and presenting amplified radiationimages which correspond to such received energy-images, which devicecomprises, a first electrode transmissive to amplified radiation imagesto be presented, a second electrode formed of a plurality of individualsmall conducting segments electrically insulated from one another andeach having an area corresponding to the degree .of resolution desiredfor said device, material comprising electroluminesceut phosphorsandwiched between said first and second electrodes, a stratumcomprising photoconductor material, the electrical resistance of saidstratum comprising photoconductor material varying inversely with theintensity of the energy comprising energy-images to be received by saiddevice, a pair of additional electrode members physically separated fromsaid first and second electrodes and provided on opposite sides of saidstratum comprising photoconductor material, one of said pair ofadditional electrode members transmissive to energyimages to be receivedby said device, the other of said pair of. additional electrode memberscomprising a plurality of individual small conducting segmentselectrically insulated from one another and each having an areacorresponding to the degree of resolution desired for said device, eachindividual small conducting segment comprising said other of said pairof additional electrode members electrically connecting to an individualmember comprising said second electrode, said first electrode and saidone of said pair of additional electrode members adapted to be connectedacross a source of DC. potential. and means for alternately and rapidlyplacing said second electrode at a potential level at least approachingthe potential level of said first electrode.

1.1. An image-amplifying device for receiving images comprised of energywhich can be propagated through vacuum and presenting amplifiedradiation images which correspond to such received energy-images, whichdevice comprises, a foundation layer comprising opaqueelectrical-insulating material, a plurality of apertures laterallydisposed through said foundation layer, substance comprlsingphotoconductor material retained in the portion of said apertures whichare alternately disposed with respect to one another, the electricalresistance of said substance comprising photoconductor material varyinginversely with the intensity of energy comprising the energy images tobe received by said device, additional sub stance comprisingelectroluminescent phosphor retained in the remainder of said apertures,an energy-amplifying element formed by each said aperture containingphotoconductor material and one of said apertures positioned adajcentthereto and containing electroluminescent phosphor, the photoconductormaterial and electroluminescent phosphor comprising each saidenergy-amplifying element electrically connected-to one another on oneside of said foundation layer, the photoconductor material andelectroluminescent phosphor comprising each said energyamplifyingelement adapted to have a DC. potential 13 applied thereacross at theother side of said foundation layer, and means -for efiecting in a rapidmanner a substantially equipotential condition across saidelectroluminescent phosphor of each said energy-amplifying element.

12. An image-amplifying device for receiving images comprised of energywhich can be propagated through vacuum and presenting amplifiedradiation images which correspond to such received energy-images, whichdevice comprises, a foundation layer comprising opaqueelectrical-insulating material, a plurality of apertures laterallydisposed through said foundation layer, substance comprisingphotoconductor material retained in the portion of said apertures whichare alternately disposed with respect to one another, the electricalresistance of said substance comprising photoconductor material varyinginversely with the intensity of energy comprising the energy-images tobe received by said device, additional substance comprisingelectroluminescent phosphor retained in the remainder of said apertures,an energy-amplifying element formed by each said aperture containingphotoconductor material and one of said apertures positioned adjacentthereto and containing electroluminescent phosphor, the photoconductormaterial and electroluminescent phosphor comprising each saidenergyamplifying element electrically connected to one another on oneside of said foundation layer, the photoconductor material andelectroluminescent phosphor comprising each said energy-amplifyingelement adapted to have a DC. potential applied thereacross at the otherside of said foundation, a conducting vibrator adapted to contact in arapid and alternating fashion the one side of said foundation layer onwhich said photoconductor material and electroluminescent phosphorcomprising each said energy-amplifying element electrically connect toone another, and said conducting vibrator adapted to have electricalcontinuity with the pole of the DC. potential adapted to be applied tosaid electroluminescent phosphor comprising each said energy-amplifyingelement.

13. An image-amplifying device for receiving images comprised of energywhich can be propagated through vacuum and presenting amplifiedradiation images which correspond to such received energy-images, whichdevice comprises, a foundation layer comprising opaqueelectrical-insulating material, a plurality of apertures laterallydisposed through said foundation layer, substance comprisingphotoconductor material retained in the portion of said apertures whichare alternately disposed with respect to one another, the electricalresistance of said substance comprising photoconductor material varyingin- Wersely with the intensity of energy comprising the energyimages tobe received by said device, additional substance comprisingelectroluminescent phosphor retained in the remainder of said apertures,an energy-amplifying element formed by each said aperture containingphotoconductor material and one of said apertures positioned adjacentthereto and containing electroluminescent phosphor, the photoconductormaterial and electroluminescent phosphor comprising each saidenergy-amplifying element electrically connected to one another on oneside of said foundation layer, the photoconductor material andelectroluminescent phosphor comprising each said energy-ampli- 'fyingelement adapted to have a DC. potential applied thereacross at the otherside of said foundation, a conducting vibrator adapted to contact in arapid and alternating fashion the one side of said foundation layer onwhich said photoconductor material and electroluminescent phosphorcomprising each said energy-amplifying element electrically connect toone another, said conducting vibrator adapted to have electricalcontinuity with the pole of the DC. potential adapted to be applied tosaid electroluminescent phosphor comprising each said energy-amplifyingelement, and said conducting vibrator being radiation transmitting inlocations disposed adjacent to said electroluminescent phosphor of eachsaid energy-amplitying element.

References Cited in the file of this patent UNITED STATES PATENTS2,566,349 Mager Sept. 4, 1951 2,650,310 White Aug. 25, 1953 2,839,690Kazan June 17, 1958 2,873,380 Kazan Feb. 10, 1959

